Re: User searchbox and RegEx best-practice - C# Discussion Boards

Re: Trouble with Invocation, serial port

Alan N18-Sep-08 1:46

18-Sep-08 1:46

Hi,
I think the problem is that your are opening your serial port before the form has been created.

Move the following code into the forms Load event handler and I think you'll be ok.

sp = new System.IO.Ports.SerialPort();
sp.PortName = "COM5";
sp.BaudRate = 19200;
sp.Parity = Parity.None;
sp.DataBits = 8;
sp.StopBits = StopBits.One;
sp.ReadTimeout = 5000;
sp.Open();
sp.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived);

Alan.

Re: Trouble with Invocation, serial port

introuble218-Sep-08 2:07

introuble2

18-Sep-08 2:07

I dont think i have a forms load event handler. Should i move the sp.init inside the InitializeComponent method?

Sigh | :sigh:

Re: Trouble with Invocation, serial port

Searril18-Sep-08 9:01

Searril

18-Sep-08 9:01

Double click on the form and you will have a Form Load event Smile | :)

Or maybe I am misunderstanding what you are asking.

Re: Trouble with Invocation, serial port

introuble219-Sep-08 2:02

introuble2

19-Sep-08 2:02

Thx, but it did not help, the error remains the same. Could it be something with the incorrect format of data on first send?

Re: Trouble with Invocation, serial port

Searril19-Sep-08 10:14

Searril

19-Sep-08 10:14

I don't know what is causing your error of course, but if you are unsure that what you are getting in the first receive is valid why not look at it and see? Or something as simple as using .TryParse() to let you know if what you are getting can be easily converted to the int32 you are looking for.

User searchbox and RegEx best-practice

ArneKruger17-Sep-08 21:56

ArneKruger

17-Sep-08 21:56

Hi there!

I am currently developing a small database frontend for private use. Obviously I want to search the various collections of business objects I pull out of the database. The search term is entered by the user and should allow for dos-stlyed wildcards (*, ?, #). In the old VB days there was this nice "like" operator (don't flame on me, please!) but since I moved on to c# there is no such thing.

I realize that Regular Expressions are the way to go, but I am unshure on how to implement these old wildcards. Pure RegEx are not an option since I find these to be much to complex for the casual user.
My current solution involves simple find & replace to transform a wildcard-expression into a valid RegEx:

<br />
criteria = criteria.Replace("?", @"\w(1)");<br />
criteria = criteria.Replace("#", @"\d(1)");<br />
criteria = criteria.Replace("*", @".*");<br />
<br />
string regex;<br />
RegexOptions options = RegexOptions.Singleline;<br />
<br />
if (IgnoreCase)<br />
 options = options | RegexOptions.IgnoreCase;<br />
<br />
 if (WholeWortsOnly)<br />
 {<br />
   regex = string.Format(System.Globalization.CultureInfo.InvariantCulture, @"(^{0}$|^{0}\s+|\s+{0}$|\s+{0}\s+)", criteria);<br />
 }<br />
 else<br />
 {<br />
   regex = criteria;<br />
 }<br />
<br />
if (criteria.Length == 0)<br />
{<br />
  regex = @"^.{0}$";<br />
}<br />
<br />
RegEx matchRegex = new Regex(regex, options);<br />
<br />

Obviously there are quite some possibilities for the user to bust this code: entering characters with RegEx-specific meaning (^, \, $ ...) will lead to exceptions or unexpected behaviour.

My question is: how do you tackle such thing?

best regards
Arne

Re: User searchbox and RegEx best-practice

leppie17-Sep-08 22:27

leppie

17-Sep-08 22:27

ArneKruger wrote:
My question is: how do you tackle such thing?

Regex.Escape()

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Re: User searchbox and RegEx best-practice

ArneKruger17-Sep-08 23:37

ArneKruger

17-Sep-08 23:37

Thanks!

I think I finally got the thing working. The problem with RegEx.Escape was that the dos-style wildcards (*, ?, #) were also escaped by the RegEx.Escape(..) method. I had to perform some preparsing.

Proper use of Tag property

Mycroft Holmes17-Sep-08 21:47

Mycroft Holmes

17-Sep-08 21:47

I have always used the Tag property eg when loading a listview I put the row ID into the tag property and use it to locate the row in a table when any processing is done. The same with the treeview, stick the ID into the nodes tag property.

Recently I have seen samples where the object is put into the tag property eg. the datarow instead of the ID value. Certainly makes management easier, I no longer have to go looking for the datarow.

Question is, are there any drawbacks to using the Tag property in this way.

Never underestimate the power of human stupidity
RAH

Re: Proper use of Tag property

N a v a n e e t h17-Sep-08 21:55

N a v a n e e t h

17-Sep-08 21:55

I don't think so. I always used to keep custom class objects in the tag property and worked well so far. Only problem I felt is casting. Each time you have to cast it back from object.

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Re: Proper use of Tag property

Mycroft Holmes17-Sep-08 22:08

Mycroft Holmes

17-Sep-08 22:08

Casting has still got to be easier than hunting down a record in a dataview ot table.

Never underestimate the power of human stupidity
RAH

Re: Proper use of Tag property

Pete O'Hanlon17-Sep-08 21:58

Pete O'Hanlon

17-Sep-08 21:58

Mycroft Holmes wrote:
Question is, are there any drawbacks to using the Tag property in this way.

Yup. Memory consumption. You have a play off here between convenience for the developer and possibly a slowdown of the system due to you having to retrieve data based on the tag. The more data you have stored, the greater the memory consumption.

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Re: Proper use of Tag property

Mycroft Holmes17-Sep-08 22:00

Mycroft Holmes

17-Sep-08 22:00

However if I'm retaining the table as a form variable (often the case) there should be no additional cost.

Never underestimate the power of human stupidity
RAH

Re: Proper use of Tag property

N a v a n e e t h17-Sep-08 22:03

N a v a n e e t h

17-Sep-08 22:03

Usually Tag is used to keep objects which are already created like DataRow or a ListView item. So it is keeping a reference to the actual object. Hence, memory consumption won't be an issue I think.

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Re: Proper use of Tag property

Pete O'Hanlon17-Sep-08 22:32

Pete O'Hanlon

17-Sep-08 22:32

N a v a n e e t h wrote:
Usually Tag is used to keep objects which are already created like DataRow or a ListView item.

That assumes that you're keeping them, rather than letting them die off and storing the id in the tag field.

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Re: Proper use of Tag property

N a v a n e e t h17-Sep-08 23:50

N a v a n e e t h

17-Sep-08 23:50

Pete O'Hanlon wrote:
rather than letting them die off and storing the id in the tag field.

That objects are part of the control. So we can't let it die. We keep a reference to those object in tag. Real object data will be removed when application ends or the associated control disposes.

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authentication issue

George_George17-Sep-08 21:40

George_George

17-Sep-08 21:40

Hello everyone,

I am accessing a web site using Windows Integrated authentication. I and the web server are in the same domain using IIS 6.0. Server runs on Windows Server 2003 and the client runs on Windows Vista.

When using the following code segment, there is always 401 error and exception. But when I am using the System.Net.CredentialCache.DefaultCredentials, the code runs successfully. Any ideas what is wrong?

try
 {
     HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://TestWeb/Monitor");

     NetworkCredential myCred = new NetworkCredential("domain\\user", "mypass");
     CredentialCache myCredentialCache = new CredentialCache();
     myCredentialCache.Add(new Uri("http://TestWeb/Monitor"), "NTLM", myCred);
     req.Credentials = myCredentialCache;

     req.ContentType = "text/xml";
     req.Method = "GET";
     req.Accept = "text/xml";

     WebResponse resp = req.GetResponse();
     StreamReader sr = new StreamReader(resp.GetResponseStream());
     Console.Write(sr.ReadToEnd()); //Just output XML response
 }
 catch (Exception ex)
 {
     Console.WriteLine(ex.ToString());
 }

thanks in advance,
George

Re: authentication issue

leppie17-Sep-08 22:21

leppie

17-Sep-08 22:21

George_George wrote:
NetworkCredential myCred = new NetworkCredential("domain\\user", "mypass");

Try the constructor taking 3 arguments. Seems it might mess up on the domain part.

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Re: authentication issue

George_George17-Sep-08 23:01

George_George

17-Sep-08 23:01

Thanks leppie,

I have tried when specifying the 3rd parameter domain, it works. But when keep the 3rd parameter to be null, it does not work. My confusion is, I think the two approaches are the same

- keep user name as Testdomain/George, and domain value to be null;
- specifying the user name George and domain to be Testdomain separately.

Just like when we log into Windows, we can enter Testdomain/George to be user name and we can also specify domain and user name separately.

Any comments?

regards,
George

Re: authentication issue

leppie17-Sep-08 23:06

leppie

17-Sep-08 23:06

George_George wrote:
My confusion is, I think the two approaches are the same

Looking at the code via Reflector shows you, it is in fact not the same. Why it is like that, I have no idea Poke tongue | ;-P

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Re: authentication issue

George_George17-Sep-08 23:24

George_George

17-Sep-08 23:24

Thanks leppie,

Which methods in Reflector are you comparing to and see whether they are of the same or different? I have the Reflector at hand and want to have the same page with you. Smile | :)

regards,
George

Re: authentication issue

leppie17-Sep-08 23:40

leppie

17-Sep-08 23:40

George_George wrote:
Which methods in Reflector are you comparing to and see whether they are of the same or different? I have the Reflector at hand and want to have the same page with you.

I am looking at:

public NetworkCredential(string userName, string password) 
  : this(userName, password, string.Empty)
{
}

Note the 3rd parameter is an empty string, and not the domain. Drilling into the called constructor, you will see no such seperation of username/domainname is taking place.

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IronScheme - 1.0 alpha 4a out now (29 May 2008)
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Re: authentication issue

George_George18-Sep-08 0:01

George_George

18-Sep-08 0:01